Highly resistive epitaxial Mg-doped GdN thin films

TL;DR

This study demonstrates the successful growth of highly resistive Mg-doped GdN thin films via molecular beam epitaxy, maintaining high crystalline quality and revealing magnetic property changes linked to electron density.

Contribution

It introduces a method to produce highly resistive Mg-doped GdN films with preserved crystalline quality and explores the magnetic behavior related to doping levels.

Findings

Resistivities of 1000 Ω·cm achieved in Mg-doped GdN

Crystalline quality comparable to undoped GdN

Decrease in Curie temperature with lower electron density

Abstract

We report the growth by molecular beam epitaxy of highly resistive GdN, using intentional doping with magnesium. Mg-doped GdN layers with resistivities of 1000 {\Omega}.cm and carrier concentrations of 10E16 cm-3 are obtained for films with Mg concentrations up to 5 x 10E19 atoms/cm3. X-ray diffraction rocking curves indicate that Mg-doped GdN films have crystalline quality very similar to undoped GdN films, showing that the Mg doping did not affect the structural properties of the films. A decrease of the Curie temperature with decreasing the electron density is observed, supporting a recently suggested magnetic polaron scenario [F. Natali et al., Phys. Rev. B 87, 035202 (2013)].